Fats And Carbohydrates Shorten Life Expectancy

The mice live longest when their food high in carbohydrates, high in protein and low fat. In addition, the new study result demonstrates that increased muscle activity can compensate for the negative effects of a high-fat diet.

Worldwide, the number of morbidly obese people is growing. This increases the risk of massive obesity cardiovascular diseases, diabetes and certain types of cancer, which is associated with reduced life expectancy. Scientists, therefore, ask the question of which diet is best to increase life expectancy. Until now there are no results from controlled long-term studies to track where people live long with a prescribed diet. Therefore, scientists resort to animal models to study diet-related long-term effects on life expectancy.

The scientists led by Susanne Klaus, German Institute for Nutrition Research (DIfE) conducted a comprehensive study on mice. One of the two study groups of mice were genetically altered so that they spent on their muscles a lot of energy. The other group of mice corresponded to the unmodified wild type. From the eleventh week of life, the mice were up to their natural end of one of three diets that varied with regard to the macronutrient composition.

The mice lived longest when they received low-fat food. The shortest life expectancy (about 550 days) had the mice, which increased rapidly in weight. For these, there were the wild-type animals that ate the fat-and carbohydrate-rich foods. The mice with increased muscle activity decreased with the same diet as well, but somewhat less and much slower. They lived on average about 230 days longer.

The second high-fat food mixture with plenty of protein and little carbohydrates resulted in wild-type mice with similar effects, although this increase is not quite as strong and fast and they lived about 754 days. By contrast, the mice burned more energy in their muscles and lived just as long as under the low-fat food, that is approximately 850 days.

"This shows that increased muscle activity can significantly help to offset the negative impact of a high-fat diet," says Susan Keiper, the lead author of the study. "Furthermore, our data suggest that most rapid weight gain during adolescence reduces the lifetime," adds Susanne Klaus. "If you were to transfer the data to humans, so people who eat very high fat, to pay sufficient exercise and avoid especially at a young age a strong weight gain".